The long-term goal of this project is to understand te genetic basis of quantitative variation in longevity in terms of phenotypic and molecular variation at individual loci, using Drosophila melanogaster as a model system. The immediate goals for this project period are: To identify new candidate genes that increase and decrease adult lifespan, using a screen for P element insertional mutations with quantitative effects on longevity in a highly inbred, on-mutant background. To identify gene regions and genetic loci contributing to naturally occurring variation in longevity, using quantitative complementation to deficiencies and mutations at candidate loci. To use linkage disequilibrium mapping of a large sample of alleles form a randomly mating population to map the QTN (quantitative trait nucleotides) responsible for naturally occurring variation in lifespan.